Numerical Study of Horizontal Proppant Flow and Transport in a Narrow Hydraulic Fracture

This study focuses on micro-mechanical understanding of horizontal proppant flow and transport in a narrow hydraulic fracture. This research is motivated by problems encountered in practice related to proppant placement problems, such as proppant pack formation in shear fractures, and clogging and bridging. For this study a numerical Discrete Element Method coupled with Continuum Fluid Dynamics and new user-defined contact model are used. Particles contact model accounts for lubrication of a thin fluid layer between two approaching particles and dissipate their kinetic energy. Consequently, particles that are driven towards each other by the shear flow stay nearby each other and form clusters. Higher particle concentration and interaction with walls in narrow fracture enhances proppant agglomeration. As a result, stable and unstable packs significantly decrease an overall efficiency of proppant placement, causing abruption of fluid flow and proppant transport. The results of the study give a new understanding of pressure, fluid viscosity, proppant concentration and size, and fracture width on the difference between horizontal proppant and fluid velocities in the fracture and clogging of narrow channels with proppant.